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Proceedings Paper

Interferometric imaging of geostationary satellites
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Paper Abstract

Even the longest geosatellite, at 40 m, subtends only 0.2 arcsec (1 microradian). Determining structure and orientation with 10 cm resolution requires a 90 m telescope at visual wavelengths, or an interferometer. We de- scribe the application of optical interferometry to observations of complex extended targets such as geosatellites, and discuss some of its challenges. We brie y describe our Navy Optical Interferometer (NOI) group's eorts toward interferometric observations of geosatellites, including the rst interferometric detection of a geosatellite. The NOI observes in 16 spectral channels (550{850 nm) using up to six 12-cm apertures, with baselines (separa- tions between apertures) of 16 to 79 m. We detected the geosatellite DirecTV-9S during glint seasons in March 2008 and March 2009, using a single 16 m baseline (resolution 1:6 m). Fringes on a longer baseline were too weak because the large-scale structure was over-resolved. The fringe strengths are consistent with a combination of two size scales, 1:3 m and & 3:5 m. Our near term NOI work is directed toward observing geosatellites with three or more 10 to 15 m baselines, using closure phase measurements to remove atmospheric turbulence eects and coherent data averaging to increase the SNR. Beyond the two- to three-year time frame, we plan to install larger apertures (1.4 and 1.8 m), allowing observations outside glint season, and to develop baseline bootstrap- ping, building long baselines from chains of short baselines, to avoid over-resolution while increasing maximum resolution. Our ultimate goal is to develop the design parameters for dedicated satellite imaging interferometry.

Paper Details

Date Published: 24 May 2012
PDF: 8 pages
Proc. SPIE 8385, Sensors and Systems for Space Applications V, 83850D (24 May 2012); doi: 10.1117/12.919381
Show Author Affiliations
J. T. Armstrong, U.S. Naval Research Lab. (United States)
E. K. Baines, U.S. Naval Research Lab. (United States)
R. B. Hindsley, U.S. Naval Research Lab. (United States)
H. R. Schmitt, Computational Physics, Inc. (United States)
S. R. Restaino, U.S. Naval Research Lab. (United States)
A. M. Jorgensen, New Mexico Institute of Mining and Technology (United States)
D. Mozurkewich, Seabrook Engineering (United States)

Published in SPIE Proceedings Vol. 8385:
Sensors and Systems for Space Applications V
Khanh D. Pham; Joseph L. Cox; Richard T. Howard; Henry Zmuda, Editor(s)

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